Evaluation of a Three-Dimensional Primary Human Hepatocyte Spheroid Model: Adoption and Industrialization for the Enhanced Detection of Drug-Induced Liver Injury.

Drug-induced liver injury is a leading cause of compound attrition during both preclinical and clinical drug development, and early strategies are in place to tackle this recurring problem. Human-relevant in vitro models that are more predictive of hepatotoxicity hazard identification, and that could be employed earlier in the drug discovery process, would improve the quality of drug candidate selection and help reduce attrition. We present an evaluation of four human hepatocyte in vitro models of increasing culture complexity (i.e., two-dimensional (2D) HepG2 monolayers, hepatocyte sandwich cultures, three-dimensional (3D) hepatocyte spheroids, and precision-cut liver slices), using the same tool compounds, viability end points, and culture time points. Having established the improved prediction potential of the 3D hepatocyte spheroid model, we describe implementing this model into an industrial screening setting, where the challenge was matching the complexity of the culture system with the scale and throughput required. Following further qualification and miniaturization into a 384-well, high-throughput screening format, data was generated on 199 compounds. This clearly demonstrated the ability to capture a greater number of severe hepatotoxins versus the current routine 2D HepG2 monolayer assay while continuing to flag no false-positive compounds. The industrialization and miniaturization of the 3D hepatocyte spheroid complex in vitro model demonstrates a significant step toward reducing drug attrition and improving the quality and safety of drugs, while retaining the flexibility for future improvements, and has replaced the routine use of the 2D HepG2 monolayer assay at GlaxoSmithKline.

Crystal structure of idelalisib tert-butanol monosolvate dihydrate.

In the title structure, 5-fluoro-3-phenyl-2-[(1S)-1-(9H-purin-6-yl-amino)-prop-yl]quinazolin-4(3H)-one (= idelalisib) tert-butanol monosolvate dihydrate, C22H18FN7O·C4H10O·2H2O, the idelalisib mol-ecule displays planar quinazoline and purine systems which are nearly perpendicular to one another. Seven distinct hydrogen-bonding inter-actions link the idelalisib, t-BuOH and water mol-ecules into a complex chain structure with the topology of a 2,3,4,5-connected 4-nodal net having the point symbol (3.4.52.62)(3.4.52.64.72)(3.5.6)(5).

Impact of Shared Decision Making on Disease-Modifying Drug Adherence in Multiple Sclerosis.

BACKGROUND: Shared decision making (SDM) and adherence to treatment are an integral part of multiple sclerosis (MS) care. A collaborative process, SDM actively involves the patient, the health care provider, and an extended network in making treatment decisions. Adherence to disease-modifying drug therapies in patients with MS presents an ongoing challenge for patients and health care providers due to the chronic nature of this disease. This narrative review aims to explore the impact of SDM on adherence based on existing literature and to identify new approaches to optimizing adherence. METHODS: A search was conducted using medical subject heading terms, including decision-making, adherence, shared decision-making, compliance, and patient-centered care. RESULTS: Shared decision making between patients and clinicians promotes adherence to the treatment plan in MS. A proactive SDM approach is based on patient preferences, education, and engagement. Providing credible and accurate sources of information is essential for improving patient engagement. Home monitoring, computerized models, and active patient engagement are a few new approaches to improve adherence in patients with MS. CONCLUSIONS: Shared decision-making interventions can have a positive effect on patient adherence to disease-modifying drug therapy in MS care. A range of new strategies is emerging that may help promote optimal disease management.

Mechanisms driving the lactate switch in Chinese hamster ovary cells.

The metabolism of Chinese Hamster Ovary (CHO) cells in a production environment has been extensively investigated. However, a key metabolic transition, the switch from lactate production to lactate consumption, remains enigmatic. Though commonly observed in CHO cultures, the mechanism(s) by which this metabolic shift is triggered is unknown. Despite this, efforts to control the switch have emerged due to the association of lactate consumption with improved cell growth and productivity. This review aims to consolidate current theories surrounding the lactate switch. The influence of pH, NAD+ /NADH, pyruvate availability and mitochondrial function on lactate consumption are explored. A hypothesis based on the cellular redox state is put forward to explain the onset of lactate consumption. Various techniques implemented to control the lactate switch, including manipulation of the culture environment, genetic engineering, and cell line selection are also discussed.

Comparison of Hepatic 2D Sandwich Cultures and 3D Spheroids for Long-term Toxicity Applications: A Multicenter Study.

Primary human hepatocytes (PHHs) are commonly used for in vitro studies of drug-induced liver injury. However, when cultured as 2D monolayers, PHH lose crucial hepatic functions within hours. This dedifferentiation can be ameliorated when PHHs are cultured in sandwich configuration (2Dsw), particularly when cultures are regularly re-overlaid with extracellular matrix, or as 3D spheroids. In this study, the 6 participating laboratories evaluated the robustness of these 2 model systems made from cryopreserved PHH from the same donors considering both inter-donor and inter-laboratory variability and compared their suitability for use in repeated-dose toxicity studies using 5 different hepatotoxins with different toxicity mechanisms. We found that expression levels of proteins involved in drug absorption, distribution, metabolism, and excretion, as well as catalytic activities of 5 different CYPs, were significantly higher in 3D spheroid cultures, potentially affecting the exposure of the cells to drugs and their metabolites. Furthermore, global proteomic analyses revealed that PHH in 3D spheroid configuration were temporally stable whereas proteomes from the same donors in 2Dsw cultures showed substantial alterations in protein expression patterns over the 14 days in culture. Overall, spheroid cultures were more sensitive to the hepatotoxic compounds investigated, particularly upon long-term exposures, across testing sites with little inter-laboratory or inter-donor variability. The data presented here suggest that repeated-dosing regimens improve the predictivity of in vitro toxicity assays, and that PHH spheroids provide a sensitive and robust system for long-term mechanistic studies of drug-induced hepatotoxicity, whereas the 2Dsw system has a more dedifferentiated phenotype and lower sensitivity to detect hepatotoxicity.

Test systems in drug discovery for hazard identification and risk assessment of human drug-induced liver injury.

INTRODUCTION: The liver is an important target for drug-induced toxicities. Early detection of hepatotoxic drugs requires use of well-characterized test systems, yet current knowledge, gaps and limitations of tests employed remains an important issue for drug development. Areas Covered: The current state of the science, understanding and application of test systems in use for the detection of drug-induced cytotoxicity, mitochondrial toxicity, cholestasis and inflammation is summarized. The test systems highlighted herein cover mostly in vitro and some in vivo models and endpoint measurements used in the assessment of small molecule toxic liabilities. Opportunities for research efforts in areas necessitating the development of specific tests and improved mechanistic understanding are highlighted. Expert Opinion: Use of in vitro test systems for safety optimization will remain a core activity in drug discovery. Substantial inroads have been made with a number of assays established for human Drug-induced Liver Injury. There nevertheless remain significant gaps with a need for improved in vitro tools and novel tests to address specific mechanisms of human Drug-Induced Liver Injury. Progress in these areas will necessitate not only models fit for application, but also mechanistic understanding of how chemical insult on the liver occurs in order to identify translational and quantifiable readouts for decision-making.

Doxorubicin in vivo rapidly alters expression and translation of myocardial electron transport chain genes, leads to ATP loss and caspase 3 activation.

BACKGROUND: Doxorubicin is one of the most effective anti-cancer drugs but its use is limited by cumulative cardiotoxicity that restricts lifetime dose. Redox damage is one of the most accepted mechanisms of toxicity, but not fully substantiated. Moreover doxorubicin is not an efficient redox cycling compound due to its low redox potential. Here we used genomic and chemical systems approaches in vivo to investigate the mechanisms of doxorubicin cardiotoxicity, and specifically test the hypothesis of redox cycling mediated cardiotoxicity. METHODOLOGY/PRINCIPAL FINDINGS: Mice were treated with an acute dose of either doxorubicin (DOX) (15 mg/kg) or 2,3-dimethoxy-1,4-naphthoquinone (DMNQ) (25 mg/kg). DMNQ is a more efficient redox cycling agent than DOX but unlike DOX has limited ability to inhibit gene transcription and DNA replication. This allowed specific testing of the redox hypothesis for cardiotoxicity. An acute dose was used to avoid pathophysiological effects in the genomic analysis. However similar data were obtained with a chronic model, but are not specifically presented. All data are deposited in the Gene Expression Omnibus (GEO). Pathway and biochemical analysis of cardiac global gene transcription and mRNA translation data derived at time points from 5 min after an acute exposure in vivo showed a pronounced effect on electron transport chain activity. This led to loss of ATP, increased AMPK expression, mitochondrial genome amplification and activation of caspase 3. No data gathered with either compound indicated general redox damage, though site specific redox damage in mitochondria cannot be entirely discounted. CONCLUSIONS/SIGNIFICANCE: These data indicate the major mechanism of doxorubicin cardiotoxicity is via damage or inhibition of the electron transport chain and not general redox stress. There is a rapid response at transcriptional and translational level of many of the genes coding for proteins of the electron transport chain complexes. Still though ATP loss occurs with activation caspase 3 and these events probably account for the heart damage.

Ventricular dilation is associated with improved cardiovascular performance and survival in sepsis.

OBJECTIVES: Myocardial dysfunction in sepsis may be associated with changes in left ventricular (LV) size. The goal of this study was to evaluate the impact of myocardial dysfunction and changes in LV diameter on hemodynamics and survival in a murine model of sepsis. METHODS: C57Bl/6 mice (N = 30) were used. Septic mice (n = 24) had cecal ligation and puncture (CLP) followed by fluid and antibiotic resuscitation and control mice (n = 6) received sham ligation. Echocardiography with a 30-mHz probe was performed at baseline and at frequent predefined time points after CLP. Stroke volume (SV), cardiac output (CO), LV internal diameter in diastole (LVIDd), and fractional shortening (FS) were measured. LV dilation was prospectively defined as an increase in LVIDd ≥ 5% from baseline values. Septic animals were classified as dilators or nondilators. RESULTS: Among septic animals, 37% were dilators and 63% were nondilators. After CLP, SV and CO decreased early in both groups. With resuscitation, SV and CO improved to a greater extent in dilators than nondilators (for SV, 46.0 ± 8.2 vs 36.1 ± 12.7 µL at 24 h, P = .05; for CO, 20.4 ± 4.8 vs 14.8 ± 6.7 mL/min, P = .04). Survival at 72 h was significantly improved in dilators compared with nondilators (88% vs 40%, P = .01). CONCLUSIONS: In a clinically relevant murine model of sepsis, animals with LV dilation had better cardiovascular performance and increased survival. Our results suggest that LV dilation is associated with improved SV and CO, a pattern resulting in greatly improved survival. These studies highlight the importance of diastolic function in septic shock.

Fluid resuscitation influences cardiovascular performance and mortality in a murine model of sepsis.

RATIONALE: Current murine models of sepsis do not account for the effects of aggressive fluid resuscitation on hemodynamics and mortality. OBJECTIVES: Evaluate the impact of fluid resuscitation regimens on cardiovascular performance and survival in a murine model of sepsis. METHODS: Mice (n = 90) were made septic by cecal ligation and puncture (CLP), and received antibiotics plus Low, Intermediate, or High fluid resuscitation regimens. Stroke volume (SV), cardiac output (CO), and fractional shortening (FS) were measured by echocardiography at predefined time points. MEASUREMENTS AND MAIN RESULTS: Baseline echocardiographic measurements were similar in all groups. After CLP, SV and CO decreased early in all groups; High: 57.2 +/- 9.2 to 23.9 +/- 7.2 microL, and 26.8 +/- 4.9 to 13.1 +/- 5.8 ml/min; Intermediate: 52.1 +/- 7.0 to 21.5 +/- 6.6 microL, and 24.9 +/- 4.1 to 11.9 +/- 3.9 ml/min; Low: 54.0 +/- 7.0 to 20.3 +/- 5.6 microL, and 25.8 +/- 4.0 to 11.3 +/- 3.9 ml/min (P < 0.05 for all vs. baseline). With resuscitation there was a dose-dependent improvement in SV and CO (P < 0.05). At 24 h SV and CO were 44.0 +/- 13.8 microL and 20.7 +/- 8.5 ml/min in the High group, 39.8 +/- 12.3 microL and 16.7 +/- 6.5 ml/min in the Intermediate group, and 30.1 +/- 12.4 microL and 14.0 +/- 7.2 ml/min in the Low group. Survival was improved in the High fluid group (75%) compared to the Intermediate (58%) and the Low (35%) resuscitation groups (P < 0.05). CONCLUSIONS: In this model, as in human sepsis, the intensity of fluid resuscitation modulates hemodynamic response and mortality. Incorporation of early and aggressive fluid resuscitation can significantly enhances the clinical relevance of murine models of sepsis.

Evaluation of Central North American prairie management based on species diversity, life form, and individual species metrics.

Reintroduction of fire and grazing, alone or in combination, has increasingly been recognized as central to the restoration of North American mixed-grass and tallgrass prairies. Although ecological studies of these systems are abundant, they have generally been observational, or if experimental, have focused on plant species diversity. Species diversity measures alone are not sufficient to inform management, which often has goals associated with life-form groups and individual species. We examined the effects of prescribed fire, light cattle grazing, and a combination of fire and grazing on three vegetation components: species diversity, groups of species categorized by life-form, and individual species. We evaluated how successful these three treatments were in achieving specific management goals for prairies in the Iowa Loess Hills (U.S.A.). The grazing treatment promoted the greatest overall species richness, whereas grazing and burning and grazing treatments resulted in the lowest cover by woody species. Burning alone best achieved the management goals of increasing the cover and diversity of native species and reducing exotic forb and (predominantly exotic) cool-season grass cover. Species-specific responses to treatments appeared idiosyncratic (i.e., within each treatment there existed a set of species attaining their highest frequency) and nearly half of uncommon species were present in only one treatment. Because all management goals were not achieved by any one treatment, we conclude that management in this region may need refining. We suggest that a mosaic of burning and grazing (alone and in combination) may provide the greatest landscape-level species richness; however, this strategy would also likely promote the persistence of exotic species. Our results support the need to consider multiple measures, including species-specific responses, when planning and evaluating management.

Morphology and electrophysiological properties of hamster spinal dorsal horn neurons that express VGLUT2 and enkephalin.

The excitatory amino acid glutamate mediates transmission at spinal synapses, including those formed by sensory afferent fibers and by intrinsic interneurons. The identity and physiological properties of glutamatergic dorsal horn neurons are poorly characterized despite their importance in spinal sensory circuits. Moreover, many intrinsic spinal glutamatergic synapses colocalize the opioid peptide enkephalin (ENK), but the neurons to which they belong are yet to be identified. Therefore, we used immunohistochemistry and confocal microscopy to investigate expression of the VGLUT2 vesicular glutamate transporter, an isoform reported in nonprimary afferent spinal synapses, and ENK in electrophysiologically identified neurons of hamster spinal dorsal horn. VGLUT2 immunoreactivity was localized in restricted fashion to axon varicosities of neurons recorded from laminae II-V, although the occurrence of immunolabeling in individual varicosities varied widely between cells (39 +/- 36%, n = 31 neurons). ENK colocalized with VGLUT2 in up to 77% of varicosities (17 +/- 21%, n = 21 neurons). The majority of neurons expressing VGLUT2 and/or ENK had axons with dense local terminations or projections consistent with propriospinal functions. VGLUT2 and ENK labeling were not correlated with cellular morphology, intrinsic membrane properties, firing patterns, or synaptic responses to sensory afferent stimulation. However, VGLUT2 expression was significantly higher in neurons with depolarized resting membrane potential. The results are new evidence for a population of dual-function dorsal horn interneurons that might provide another mechanism for limiting excitation within dorsal horn circuits during periods of strong sensory activation.

Hyperhomocysteinemia in patients with heart failure referred for cardiac transplantation: preliminary observations.

BACKGROUND: Hyperhomocysteinemia is becoming recognized as a risk factor for cardiovascular disease, yet there are limited data on the prevalence of hyperhomocysteinemia in patients with heart failure. HYPOTHESIS: The purpose of this study was to examine the prevalence of hyperhomocysteinemia in patients with severe heart failure and to correlate serum homocysteine levels with factors that may affect homocysteine metabolism. METHODS: Serum homocysteine levels were measured at the time of cardiac transplant evaluation in 89 consecutive patients with severe heart failure. Homocysteine levels for patients with ischemic cardiomyopathy (ICM) were compared with levels obtained in patients with nonischemic cardiomyopathy (NICM), and homocysteine levels were correlated with demographic and hemodynamic parameters as well as functional status. RESULTS: The mean plasma homocysteine level was increased (14.3 +/- 5.3 micromol/l, normal <9.0 micromol/l) and was equivalent between patients with ICM versus NICM (14.7 +/- 5.8 micromol/l vs. 13.8 +/- 4.5 micromol/l, p = 0.44). Elevated homocysteine levels were seen in a large proportion (89%) of patients and were equally common to patients with NICM (94%) and ICM (85%). Serum homocysteine levels correlated with serum creatinine (r = 0.51, p < 0.001), with a history of diabetes (p = 0.028), and with a history of peripheral vascular disease (p = 0.045). Only 6% of patients were receiving folic acid therapy at the time of transplant referral. CONCLUSION: Hyperhomocysteinemia is common in patients with severe heart failure, and plasma homocysteine levels are uniformly elevated regardless of the etiology of heart failure. Elevated plasma homocysteine levels are likely a consequence of heart failure-related renal insufficiency.

Resistance exercise training and alendronate reverse glucocorticoid-induced osteoporosis in heart transplant recipients.

BACKGROUND: Immunosuppression therapy with bolus glucocorticoids causes regional osteoporosis in the axial skeleton of heart transplant recipients (HTR). No preventive strategy is generally accepted for steroid-induced bone loss. METHODS: To determine the efficacy of an anti-osteoporosis regimen that combined a bisphosphonate agent (alendronate sodium) with the osteogenic stimulus of mechanical loading, 25 HTRs were randomly assigned either to a group that received alendronate (10 mg/day) for 6 months (ALEN; n = 8), a group that received alendronate (10 mg/day) and performed specific resistance exercises for 6 months (ALEN + TRN; n = 8) or to a non-intervention control group (CONTR; n = 9). Alendronate was initiated at 2 months after transplantation. Bone mineral density (BMD) of the total body, femur neck and lumbar spine (L-2 and L-3) was measured by dual-energy X-ray absorptiometry before and 2, 5 and 8 months after transplantation. Resistance training consisted of lumbar extension exercise (MedX) performed 1 day/week and 8 variable resistance exercises (MedX) performed 2 days/week. RESULTS: Pre-transplantation BMD values did not differ among the 3 groups. BMD of the total body, femur neck and lumbar vertebra were significantly decreased below baseline at 2 months after transplantation in CONTR (-2.6 +/- 0.9%, -5.1 +/- 1.8%, -12.5 +/- 4.2%, respectively), ALEN (-2.8 +/- 0.8%, -5.3 +/- 1.6%, -12.0 +/- 3.9%) and ALEN + TRN groups (-2.7 +/- 1.0%, -5.6 +/- 2.1%, -11.2 +/- 3.7%). CONTR had further significant losses of BMD after 3 and 6 months. ALEN had no further regional BMD losses after initiation of alendronate therapy. ALEN + TRN restored BMD of the whole body, femur neck and lumbar vertebra to within 0.9%, 2.1%, and 3.4% of pre-transplantation levels, respectively. CONCLUSIONS: Resistance exercise plus alendronate was more efficacious than alendronate alone in restoring BMD in HTRs. Our results indicate that anti-osteoporosis therapy in this population should include both an anti-resorptive agent as well as an osteogenic stimulus, such as mechanical loading.

Care processes and clinical outcomes of continuous outpatient support with inotropes (COSI) in patients with refractory endstage heart failure.

BACKGROUND: This study describes the process and outcomes of continuous outpatient support with inotropes (COSI) in patients with Stage D heart failure (HF). Although Stage D HF has recently been defined as end-stage disease requiring special interventions for survival such as COSI or ventricular assist devices, concern has been raised regarding the safety, efficacy, mortality outcomes, and ethics of COSI. METHODS AND RESULTS: Inotrope dependence was defined as worsening of the patient's clinical status with attempted inotrope withdrawal such that the patient was deemed unlikely to survive to permit hospital discharge. A care process for COSI was designed; baseline and outcome variables were evaluated. COSI was administered to 36 inotrope-dependent patients (age 55.4 +/- 9.5 years, 24 males). Baseline characteristics (mean +/- SD) were consistent with Stage D HF: left ventricular ejection fraction 19.9 +/- 8.5, left ventricular end-diastolic dimension (LVEDD) 70 +/- 10 mm, systolic blood pressure 97.4 +/- 13.4 mm Hg, serum creatinine 1.5 +/- 0.6, serum sodium 131.7 +/- 5.3; 69 HF hospitalizations (mean 1.9 +/- 1.8) 6 months before COSI initiation. Symptomatic hypotension, increasing dyspnea, renal dysfunction, and hypoperfusion most commonly prevented inotrope withdrawal. Despite Stage D HF, patients were discharged with COSI ambulatory, oriented, and pain free. Rehospitalizations were 46; 6 subjects accounted for 24 hospitalizations; 23 had 0 or 1 rehospitalization. Median survival was 3.4 months (range 0.2-26.3 months); and 3-, 6-, and 12-month Kaplan Meier survival was 51%, 26%, and 6%, respectively. The majority of patients died at home and chose to not undergo resuscitation attempts. CONCLUSION: COSI may be an acceptable treatment option for Stage D HF.

Comparison of dobutamine versus milrinone therapy in hospitalized patients awaiting cardiac transplantation: a prospective, randomized trial.

BACKGROUND: The use of dobutamine or milrinone for inotropic support in patients with heart failure awaiting cardiac transplantation is largely arbitrary and based on institutional preference. The costs and effectiveness of these drugs have yet to be compared in a prospective, randomized study. METHODS: We compared clinical outcomes and costs associated with the use of dobutamine or milrinone in 36 hospitalized patients awaiting cardiac transplantation. Patients were randomly assigned to receive either dobutamine or milrinone at the time of initial hospitalization and were followed until death, transplantation, or placement of mechanical cardiac support (intra-aortic balloon pump or left ventricular assist device). RESULTS: Seventeen patients were randomly assigned to receive dobutamine (mean dose 4.1 +/- 1.4 microg/kg/min) and 19 patients received milrinone (mean dose 0.39 +/- 1.0 microg/kg/min). Therapy lasted 50 +/- 46 days for those in the dobutamine group and 63 +/- 45 days in the milrinone group. We did not detect differences between the 2 groups in right heart hemodynamics, death, need for additional vasodilator/inotropic therapy, or need for mechanical cardiac support before transplantation. Ventricular arrhythmias requiring increased antiarrhythmic therapy occurred frequently in both groups. Total acquisition cost of milrinone was significantly higher than that of dobutamine (16,270 dollars +/- 1334 vs 380 dollars +/- 533 P <.00001). CONCLUSIONS: Both dobutamine and milrinone can be used successfully as pharmacologic therapy for a bridge to heart transplantation. Despite similar clinical outcomes, treatment with milrinone incurs greater cost.

Hepatocyte polarity and the peroxisomal compartment: a comparative study.

In search of factors that regulate the phenotype of the peroxisomal compartment in wild-type liver parenchymal cells, we compared hepatocyte polarity to peroxisome differentiation, using adult liver as the standard. Differentiation parameters were evaluated in a three-dimensional culture model (spheroid), in 'sandwich' and monolayer primary hepatocyte cultures, and in 15.5 and 18.5-day-old foetal rat liver. Peroxisomes, studied by immunohistochemistry, enzyme histochemistry, and catalase specific activity, were better differentiated depending on foetal age (day 18.5 > day 15.5) and culture type (spheroid > sandwich > monolayer). The hepatocyte polarity markers ATP-, ADP-, and AMP-hydrolysing activities were, in all models, mislocalized at the lateral plasma membrane, whereas in contrast the multidrug resistance-associated protein 2 (mrp2) antigen was always correctly immunolocalized at the apical membrane domain. In cultures, the correct secretion of fluorescein (mrp2-mediated) into bile canaliculi was observed. Bile canaliculi (branching, ultrastructure and immunolocalization of the tight-junction associated protein ZO-1), were better differentiated in 18.5 than in 15.5-day-old foetal liver and in spheroid > sandwich > monolayer cultures. Our results show a parallelism between changes of the peroxisomal compartment and bile canalicular structure together with mrp2-mediated secretory function. Distinct polarization characteristics do not necessarily change simultaneously, suggesting different regulatory mechanisms.

Percutaneous coronary intervention versus medical therapy for coronary allograft vasculopathy. One center's experience.

BACKGROUND: Coronary allograft vasculopathy, a rapidly progressive form of atherosclerosis, remains the limiting factor in the long-term survival of heart transplant recipients. Some centers have attempted percutaneous coronary intervention to slow the disease process and thereby reduce mortality in these patients, but long-term follow-up data are scarce. We compared clinical outcomes in heart transplant recipients with coronary allograft vasculopathy who were treated either with percutaneous coronary intervention or with aggressive medical therapy alone. METHODS: A retrospective analysis of all heart transplant recipients at our institution who underwent surveillance coronary angiography for coronary allograft vasculopathy between 1995 and 2000 was performed. Patients with coronary allograft vasculopathy were stratified according to whether they received medical therapy or percutaneous coronary intervention. Baseline demographics, results of re-vascularization procedures and outcomes were analyzed. RESULTS: From 1995 to 2000, 301 patients underwent 602 coronary angiograms. Of the 79 patients who had angiographic evidence of coronary allograft vasculopathy, 53 were treated with aggressive medical therapy, while 26 underwent percutaneous coronary intervention in addition to aggressive medical therapy. At baseline, patients treated with aggressive medical therapy tended to be younger (54.6 +/- 13.8 years) than patients treated with percutaneous coronary intervention (62.6 +/- 7.6 years; p = 0.0079). Ejection fraction at time of diagnosis of coronary allograft vasculopathy was similar for both groups (medical therapy group, 44.4 +/- 13.4% vs percutaneous coronary intervention group, 47.2 +/- 12.7%; p = 0.38). In our cohort, heart transplant recipients with coronary allograft vasculopathy demonstrated greater mortality than heart transplant recipients without coronary allograft vasculopathy (p = 0.016). Patients who underwent percutaneous coronary intervention had a 60% re-stenosis rate at 6 months if they were treated with coronary angioplasty and an 18% re-stenosis rate if they received a coronary stent. Kaplan-Meier analysis showed no significant difference in survival in either treatment group at 1 year (80% for medical therapy group vs 95% for percutaneous coronary intervention group) or 3 years (68% for medical therapy group vs 79% for percutaneous coronary intervention group) after the angiographic diagnosis of coronary allograft vasculopathy. CONCLUSION: In this non-randomized trial, heart transplant recipients with coronary allograft vasculopathy were less likely to survive than patients without it. In addition, we found no statistical difference in mortality in heart transplant recipients with coronary allograft vasculopathy, regardless of whether they received percutaneous coronary intervention or aggressive medical therapy alone.